As environment-friendly vehicles, attention is now focused on vehicles incorporating a power storage device (for example, secondary cell or capacitor) and running by means of a driving force generated from the electric power stored in the power storage device. Such vehicles include, for example, electric vehicles, hybrid vehicles, fuel cell vehicles and the like.
Hybrid vehicles of the type capable of charging a vehicle-mounted power storage device from a power supply external to the vehicle is known, likewise with an electric vehicle. For example, there is known the so-called “plug-in hybrid vehicle” that allows the power storage device to be charged from a general household power supply by connecting the plug socket located at an establishment with the charging inlet provided at the vehicle.
As a method for power transfer, attention is recently focused on wireless electrical power transmission not using power supply cords and/or cables. Three promising approaches of this wireless power transfer technique are known, i.e. power transfer using electromagnetic induction, power transfer using electromagnetic waves, and power transfer through the resonance method.
The resonance method thereof directed to noncontact power transfer causes a pair of resonators (for example, a pair of self-resonant coils) to resonate at an electromagnetic field (near field) for electrical transmission by the electromagnetic field, allowing electric power as high as several kW to be transferred over a relatively long distance (for example, several meters).
Japanese Patent Laying-Open No. 2009-106136 (PTL 1) discloses the technique of charging a power storage device mounted on a vehicle by receiving charging power in a wireless manner from a power supply external to the vehicle by a resonance method.